scholarly journals Подъем пылевых частиц при воздействии лазерного излучения на хондритовую мишень и возможность моделирования плазменно-пылевых процессов у поверхности Луны

Author(s):  
И.Н. Бурдонский ◽  
А.Г. Леонов ◽  
В.Н. Юфа ◽  
А.П. Голубь ◽  
С.И. Попель ◽  
...  

The results of the first study on experimental modeling of the rise of dust particles by a shock wave above a target surface, performed on the Saturn installation, are presented. The interaction of laser radiation with a porous chondritic target, the surface of which contains fine particles of talc, is investigated. The results of experimental modeling can be used to describe the rise of dust particles from zones of nonlinear and linear elastic deformations of the regolith material, which characterize the impact of the meteoroid on the surface of the Moon.

2013 ◽  
Vol 79 (4) ◽  
pp. 405-411 ◽  
Author(s):  
SERGEY I. POPEL ◽  
LEV M. ZELENYI

AbstractFrom the Apollo era of exploration, it was discovered that sunlight was scattered at the terminators giving rise to “horizon glow” and “streamers” above the lunar surface. Subsequent investigations have shown that the sunlight was most likely scattered by electrostatically charged dust grains originating from the surface. A renaissance is being observed currently in investigations of the Moon. The Luna-Glob and Luna-Resource missions (the latter jointly with India) are being prepared in Russia. Some of these missions will include investigations of lunar dust. Here we discuss the future experimental investigations of lunar dust within the missions of Luna-Glob and Luna-Resource. We consider the dusty plasma system over the lunar surface and determine the maximum height of dust rise. We describe mechanisms of formation of the dusty plasma system over the Moon and its main properties, determine distributions of electrons and dust over the lunar surface, and show a possibility of rising dust particles over the surface of the illuminated part of the Moon in the entire range of lunar latitudes. Finally, we discuss the effect of condensation of micrometeoriod substance during the expansion of the impact plume and show that this effect is important from the viewpoint of explanation of dust particle rise to high altitudes in addition to the dusty plasma effects.


2021 ◽  
Vol 938 (1) ◽  
pp. 012011
Author(s):  
V. Ya. Manokhin ◽  
M. V. Manokhin

Abstract The paper considers the emissions of pollutants from road transport, in the total air pollution they make up 70 % on the example of a particular metropolis. The highway is considered as a linear source consisting of single point sources of pollution. Special attention is paid to suspended fine particles in the solid phase. It is determined that when assessing the level of environmental pollution, it is important to take into account not only the total number of vehicles, but also the ratio of cars of different categories, since they, having different emission factors, supply unequal volumes (mass) exhaust gas components. The variability of the traffic flow density on the streets of six administrative districts of Voronezh and the complexity of zoning the city territory because of three-year monitoring were established. It is proposed to place accounting points on streets that differ in their status in the general transport network of the city in order to obtain reliable data during the monitoring period [11]. The simulation of diffusion movements and migrations of solid-phase air pollutants of roadside territories is carried out. The model of diffusive displacements and migrations of heavy metals is considered in relation only to passive contaminants. The choice is implemented and the method of studying the level of dustiness of motor transport roads is recommended, which allows fixing dust particles from 0.1 microns to 250 microns in the air. An algorithm of an improved system for monitoring the content of fine dust in the atmosphere of a residential zone is proposed. [16]. To minimize the emission of suspended substances, a two-stage emission purification system consisting of a gas-liquid absorber and a catalytic adsorber is proposed.


1974 ◽  
Vol 41 (1) ◽  
pp. 124-130 ◽  
Author(s):  
C. A˚ke Persson

The variation of shock pressure with the angle between the colliding surfaces in an oblique impact between two plane plates is analyzed theoretically. The analysis is carried out for small impact angles and the plate materials are assumed to behave like fluids (Case 1) and linear elastic media (Case 2). In the latter case the two extreme assumptions concerning the friction at the interface, no friction and no sliding, are treated. The results show that the shock pressure increases quadratically with the impact angle (except for some of the no sliding cases, where decreasing pressure can occur) and that the pressure rise is strongly dependent upon the ratio between the impact velocity and the shock wave velocities for the plate materials.


2021 ◽  
Author(s):  
Nikhil Prakash Joshi ◽  
Jonathan Lewis Brewer ◽  
Christopher John Rose

Abstract During the annual In-Service Inspection of a spar hull, several regions of pitting corrosion on the upper portion of the north and south moon pool external wall plating were identified. The moon pool walls are constructed as typical stiffened panel structures. Visual, ultrasonic (UT), and pulsed eddy current (PEC) inspections indicated regions of corrosion with roughly 40% to 70% averaged localized wall loss. This paper discusses the analytical assessment of the structure to determine the effect of the corrosion on the structural integrity of the moon pool wall and any similar structural panel. To determine the impact of corrosion on the stiffened panel integrity, a finite element (FE) based analysis approach is used to perform a comparative assessment of the "as-built" and "corroded" configuration of the moon pool wall. The nominal plate and stiffener thicknesses are modeled in the "as-built" configuration; whereas, the measured plate thickness from the inspection is modeled in the "corroded" configuration. The structure is subjected to design loads based on the storm damaged design condition. The analysis is performed by uniformly increasing the applied loads until failure occurs, maintaining a constant ratio between the nominal loads. Two different analyses are performed as a part of the strength assessment: (1) a linear-elastic eigenvalue analysis to estimate the elastic buckling capacity and mode shapes of the structure and (2) an elastic-plastic post-buckling analysis to estimate the ultimate capacity of the structure. In addition, the results from the linear-elastic eigenvalue analysis are compared to the results from analytical buckling calculations. The analysis results indicate that the corrosion reduces the elastic plate buckling capacity significantly. However, the overall capacity of the stiffened panel is not significantly reduced. Therefore, from a global strength perspective, the stiffened panel remains acceptable in its corroded condition. The upper portion of the moon pool wall is typically fatigue insensitive in spars. Therefore, the effect of the corrosion wall loss on the fatigue performance was not assessed. Since there is limited guidance in design and assessment codes for assessing corroded stiffened panels, this approach can be used to address future stiffened panel corrosion wall loss. In addition, this method allows for inclusion of future corrosion allowance, if applicable. Determining the capacity of corroded panels using FEA-based numerical methods, like those described in this paper, allows the operators to manage their risks, repair costs, and inspection frequency by determining the actual capacity of the damaged components. This allows the operators to determine the appropriate mitigation measures based on a quantitative risk calculation.


2021 ◽  
Author(s):  
Boris Ivanov

<p>We continue the analysis of HiRISE high resolution images of Mars to understand properties of dust covering the surface. The data on dust devils observed with Mars landers and surface traces of dust devils could be expanded with elongated albedo features imaged near “new” impact sites (“new” means that we have orbital images before and after the meteoroid impact, which give us an estimate of the impact date and the age of a feature). The age of these features is from 0.5 to 12 terrestrial years. From geometric reasons we could assume that the most possible mechanism of this elongated albedo details is the “footprint” of two or more colliding air shock waves, generated at the impact site. Of ~1200 “new” impacts known today, in 18 cases crater pairs or clusters, created with fragments of the same “parent” meteoroid, we recognize 24 thin “parabolas” with a width of 1 to 10 m (0.2 to 10 main crater diameters, <em>D</em>), extended to 100 – 400 m (3 to 100 <em>D</em>) from the impact site. In ~30 cases near a single crater we observe a curved albedo feature nick-named “scimitar”. These features have width, growing with a distance from the impact point. The length varies from 10 to 100 <em>D</em>, the width varies from 1 to 10 <em>D</em>. Our working hypothesis is that “scimitars” are footprints of ballistic and spherical air shock wave collision at the surface. Both “parabolas” and “scimitars” have an exact bilateral symmetry, which allows us to reconstruct the flight direction of projectiles.</p><p>We estimate the equivalent energy of spherical air blasts with two different assumptions for “parabolas” and “scimitars” formation. For parabolas we assume a mechanism, similar to dust devil track formation – the negative pressure excurse uplifts the upper fine dust layer. The main assumption is that the dark parabolic strip width corresponds the wave length of the negative pressure phase in the air shock wave. It gives us the minimum energy estimate as in reality the negative phase could be longer. The negative pressures here along the parabola length decay from about 10 to 5 Pa with the phase duration of a few milliseconds. Such a suction pulse is able to mobilize dust particles 50 to 100 microns in size.</p><p>For scimitars, which in contrast to “dark” parabolas are typically “brighter” than surrounding area, we have no a good mechanical explanation of origin. However, with limits of our current model, the spherical “explosion” air blast should be enough energetic, to overrun the ballistic shock wave. From non-linear motion of the shock wave front we can estimate the fraction of meteoroid’s kinetic energy, converted to the air blast energy. The model is able to reproduce approximately the scimitar’s curvature.</p>


Author(s):  
Alexander V. Zakharov

The surface of the Moon, as well as the surface of an airless body of the solar system, is subject to constant bombardment of micrometeorites, the effects of solar radiation, solar wind, and other space factors. As a result of the impact of high-speed micrometeorites for billions of years, the silicate base of the lunar surface is crushed, turning into particles with an approximately power-law-sized distribution. Given the explosive nature of the occurrence, these particles are characterized by an extremely irregular shape with pointed edges, either droplets close to spheres or conglomerates sintered at high temperatures. The plasma of the solar wind and the solar radiation, especially its ultraviolet part of the spectrum, when interacting with the upper layer of regolith causes a charge of the regolith upper layer and creates a near-surface double layer and an electric field. In this field, regolith particles of micron and submicron sizes can break away from the surface and levitate above the surface. Such dynamic processes lead to the transfer of dust particles over the surface of the Moon, as well as to the scattering of sunlight on these particles. Glows above the lunar surface of this nature were observed by television systems of American and Soviet landers in the early stages of lunar exploration. The American astronauts who landed on the lunar surface during the Apollo program experienced the aggressive properties of lunar dust. The results of the Apollo missions showed that dust particles are one of the main causes of danger to humans, spacecraft systems, and activities on the lunar surface. Based on the results of late 20th- and early 21st-century lunar research, as well as the proposed models, the article discusses the formation of the lunar regolith and the near-surface exosphere of the Moon under the influence of external factors in outer space. Relevant considerations include the causes and conditions of dust particle dynamics, the consequences of these processes as well as possible threats to humans, engineering systems during the implementation of planned research programs, and the exploration of the Moon. Also of relevance are models of the formation of a plasma-dust exosphere, the dynamics of dust particles in the near-surface region, and dust clouds at a distance of several tens of kilometers from the Moon’s surface, based on the available experimental data. The main unresolved problems associated with the dynamics of the dust component of lunar regolith are given, and methods for solving problematic issues are discussed. The Moon research programs of leading space agencies and their role in the study of Moon dust, its dynamics, human impact, and its activities in the implementation of promising programs for the study and exploration of the Moon are examined.


2021 ◽  
Vol 346 ◽  
pp. 03070
Author(s):  
Rustem Ya. Bikkulov ◽  
Andrey V. Dmitriev ◽  
Vadim E. Zinurov ◽  
Guzel R. Badretdinova

Nowadays, at production facilities with paint-spraying booths that use paint and varnish materials to cover the surfaces of product, the problem of gas flow contamination with finely dispersed solid particles of dust and rubbish, which negatively affect the quality of products, is increasingly being raised. In order to minimize the content of solid particles in the gas flow, coarse and fine filters are installed in the paint-spraying booths, which prevent dust particles from entering the surface of products. However, the existing purification devices have a number of disadvantages that affect the efficiency of collecting finely dispersed particles from the gas flow with a size of 0.5-5 microns. The authors of article developed a square separator to increase the efficiency of collecting finely dispersed particles from gas flows in the paint-spraying booths. The installation of proposed separation device in the paint-spraying booths affects not only the quality of collecting solid particles, but also increases the service life of fine and coarse filters In the course of numerical studies, the results of impact of structural and technological parameters, namely, the impact of inlet rate and scale of separation device on the efficiency of collecting solid particles from the gas flow, were obtained.


2021 ◽  
Author(s):  
Gianmario Merisio ◽  
Vittorio Franzese ◽  
Carmine Giordano ◽  
Mauro Massari ◽  
Pierluigi Di Lizia ◽  
...  

<p>Vast amounts of meteoroids and micrometeoroids continuously enter the Earth–Moon system and consequently become a potential threat. Lunar meteoroid impacts have caused a substantial change in the lunar surface and its properties. The Moon having no atmospheric blanket to protect itself, it is subjected to impacts from meteoroids ranging from a few kilograms to 10’s of grams each day. The high impact rate on the lunar surface has important implications for future human and robotic assets that will inhabit the Moon for significant periods of time. Therefore, a greater understanding of the meteoroid population in the cislunar environment is required for future exploration of the Moon.</p> <p>Moreover, refining current meteoroid models is of paramount importance for many applications. For instance, since meteoroids may travel dispersed along the orbit of their parent body, understanding meteoroids and associated phenomena can be valuable for the study of asteroids and comets themselves. Studying meteoroid impacts can help deepening the understanding of the spatial distribution of near-Earth objects in the Solar system. The study of dust particles can be also of interest because, together with the solar wind, they determine the space weather. Finally, it is critical to be able to predict impacts by relying on accurate impact flux models. That because the impact of small asteroids with Earth, even slightly larger than meteoroids, can cause severe damage.</p> <p>In this context, the Lunar Meteoroid Impacts Observer (LUMIO) is a CubeSat mission to observe, quantify, and characterise the meteoroid impacts by detecting their flashes on the lunar far-side. This complements the knowledge gathered by Earth-based observations of the lunar nearside, thus synthesising a global information on the lunar meteoroid environment. LUMIO envisages a 12U CubeSat form-factor placed in a halo orbit at Earth-Moon L2. The mission employs the LUMIO-Cam, an optical instrument capable of detecting light flashes in the visible spectrum. LUMIO is one of the two winner of ESA’s LUCE (Lunar CubeSat for Exploration) SysNova competition, and as such it is being considered by ESA for implementation in the near future. The Phase A study has been conducted in 2020 under ESA's General Support Technology Programme (GSTP) and successfully completed at the beginning of 2021, after an independent mission assessment performed by ESA’s CDF team.</p> <p>In this work, the latest results of the Phase A study of the LUMIO lunar CubeSat will be shown. An overview of the present-day LUMIO CubeSat A design will be given, with a focus on the latest developments. An overview on how LUMIO will impact the currently existing knowledge of meteoroid models will be given supported by high-fidelity simulated data.</p>


1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.


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